1. Field of the Invention
The present invention relates to a sheet processing apparatus, and more particularly, to a sheet processing apparatus that regulates, in a width direction, a position of a sheet to be processed, and to an image forming apparatus including the sheet processing apparatus.
2. Description of the Related Art
Heretofore, as an image forming apparatus such as a copier, a printer, a facsimile machine, and a multifunctional printer, there is known an image forming apparatus main body which is provided with a sheet processing apparatus, where sheets are delivered from the image forming apparatus main body after image formation to the sheet processing apparatus which implements a process such as a binding process for the sheets. In the sheet processing apparatus, the sheets delivered from the image forming apparatus main body are transported to a sheet processing portion. Then, the sheet processing portion implements, for the delivered sheets, processes such as a stacking/aligning operation of stacking and aligning the sheets, and a stapling operation of binding the sheets.
As a conventional sheet processing apparatus, an apparatus has been disclosed, in which a sheet moving device moves the sheets in a width direction intersecting with a sheet transporting direction, and allows side edges of the sheets to abut against an abutting member, to thereby align the sheets. Here, in the sheet processing apparatus, a sheet holding-down member that suppresses curling of such side edge portions of the sheets is placed in the vicinity of the abutting member (Japanese Patent Application Laid-Open No. 2005-306528).
However, the sheet holding-down member is fixed with respect to the width direction, and hence a distance between the sheet moving device and the sheet holding-down member at the time when the sheet moving device aligns sheets of a large size becomes larger than a distance between the sheet moving device and the sheet holding-down member at the time when the sheet moving device aligns sheets of a small size. Hence, in the case of aligning the sheets of the large size, there is a fear that the sheets may buckle between the sheet moving device and the sheet holding-down member to thereby adversely affect alignment characteristics, compared with the case of aligning the sheets of the small size.